Users of cutting tools, and most particularly power tools, frequently have need of cutting or drilling their work to a precise predetermined depth. Slots, holes, bevels and dadoes often are useful only if they have a precise depth. Depth gauges exist for the measurement of these cuts, and stops and collars also exist which can be mounted on the cutting tool to prevent its penetration beyond the desired depth. Each of these is useful, and widely used by professional as well as amateur workmen. The problem of assembling these stops or collars, and changing them each time a new depth is desired, can be painstaking and time consuming, and if frequent changes are necessary, are a source of error. Placing tapes or pencil marks on the tools often is less successful, since the tapes move, or wear out, and the pencil marks usually cannot be seen while the tool is in motion.